Maximizing the Value of Recovered Materials

SEATTLE (Waste Advantage): Airspace can be considered the most important aspect of the landfill. The less material put into your landfill, the greater your airspace savings are. In this article, you will learn sustainable practices to conserve airspace. This conservation will lengthen the life of your landfill and boost your bottom line.

Materials to Divert, Recycle, or Re-use
Valuable materials should be separated and diverted from the waste stream before they go to the working face. These recovered materials may be sent off to other facilities to be recycled or internally repurposed. Materials include:
1. Scrap Metal Recycling
• Sell to Recycling Facilities
• Ferrous metals such as steel or iron can be sold for profit.
• High-value non-ferrous metals such as materials like aluminum, copper, and brass fetch higher returns.

2. Tires
• Operational Uses
• Alternate Daily Cover (ADC): Shredded tires reduce the need for soil while meeting regulatory standards
• Drainage Systems: Chips work well in leachate and gas collection layers
• Road Construction: Use chips or rubber for road bases and dust suppression
• Erosion Control: Tires stabilize slopes and prevent soil loss

3. Revenue-Generating Applications
• Tire-Derived Fuel (TDF): Sell as fuel for power plants or cement kilns
• Temporary Fencing: Whole tires can be stacked as barriers or fencing

4. Specialized Uses
• Stormwater Management: Tires can serve as fill for wetlands or retention ponds
• Final Cover: Shredded tires or whole tires help anchor tarps or stabilize landfill covers
• Weather Erosion Control: Can be used with alternative cover tarp protection during high winds

5. Wood
• ADC: Shredded wood serves as an effective daily cover when mixed with soil or sludge
• Community Reuse: Shredded wood may be given away to the community as mulch or compost chips
• Road Maintenance: Chips provide cost-effective road bases and can be used for dust control
• Leachate Management: Wood chips enhance drainage layers
• Renewable Energy: Process unusable wood into biomass fuel for power generation or pellet production

6. Concrete Aggregate
• Road Construction: Crushed concrete is durable and cost-effective for road bases or repairs
• Site Development: Concrete aggregate can be used as a backfill for constructing buildings or creating access pads and work zones
• Erosion Control: Reinforce slopes or embankments to prevent soil erosion

7. Fines
• ADC: Fines are cost-effective for daily cover, meeting odor and pest control standards
• Soil management: Fines may be used to enhance soil structure in erosion control or landscaping applications

8. Cardboard
• Recycling: Cardboard can be sent to paper recycling plants for a profit
• Business Partnerships: Collaborate with local businesses to establish a reliable supply of recyclable cardboard
• Composting: Some types of cardboard can serve as a carbon-rich material for compost

Alternate Daily Covers
Alternate daily covers are materials, besides soil, used to cover the working face outside of operating hours. This cover reduces waste from blowing, suppresses smell, and deters vermin. Each working day, the cover is removed or compacted over to continue building the trash cell. Examples of alternate daily covers are:
• Foam
• Spray on slurry
• Tarps
• Shredded materials—tires, wood, aggregate, fines, auto fluff
• Compost or green waste
• Contaminated soil and sediment
• Sludge

Soil for daily cover incurs costs from excavation equipment or outsourcing soil. Choosing to use alternate daily covers saves airspace by lowering the amount of soil that is used. Foams, slurries, or tarps will incur additional costs to the landfill, but take up less space than soil. Shredded waste will find its way into the landfill cell regardless. Why not repurpose it as a daily cover instead of compacting it and adding a layer of dirt? This results in less material being compacted and saves overhead costs.

Design and Equipment
To effectively divert waste, a sorting and recycling area should be established before the working face. Trucks unloading waste can be directed either to the sorting area or working face, depending on the type of waste. Recyclable materials should be unloaded at the sorting area, where they will be screened into the appropriate categories and shredded if applicable. Non-recyclable waste, on the other hand, will be sent directly to the working face for disposal.

Equipment like trommel screens, recycling screens, picking stations, eddy currents, and air separators can be employed to separate materials for recycling or diversion, reducing landfill waste. A shredder will be needed if shredded waste is used as daily cover; though costly, it can improve compaction rates by shredding waste before compaction. Foams and slurries require specialized spray equipment, and tarps need a roller that integrates with the compactor.
Equipment at the working face should be optimized to extend the lifespan of each cell, thereby enhancing the overall longevity of the landfill. To maximize efficiency, the equipment must be appropriately sized to handle the daily tonnage and types of waste. Landfills typically use a variety of machinery, including track loaders, water trucks, scrapers, and backhoes. However, these essential machines are always present at the landfill: dozers, landfill compactors, and excavators. When selecting a landfill compactor, choosing one that delivers superior compaction can significantly improve airspace savings, with some models offering up to 10 percent better compaction rates compared to other compactors on the market.

Courtesy: www.wasteadvantagemag.com